Efficient document boundary determination

Abstract

An imaging system includes an imaging sensing device sensing an object having a first background color and a backing in opposing relationship with the object having a second background color which is substantially the same as the first background color. The imaging system determines at least one general bounding region of the object based upon a shadow cast onto backing by the object.

1. An imaging system comprising:
 (a) an imaging device sensing an object having a first background color; 
 (b) a backing in opposing relationship with said object having a second background color substantially the same as said first background color; and 
 (c) said imaging system determines at least one general bounding region of said object based upon a shadow cast onto said backing by said object. 
 
   
   
     2. The imaging system of  claim 1  wherein said object is a substantially flat document. 
   
   
     3. The imaging system of  claim 2  wherein said backing is a cover and is substantially flat and is in face-to-face relationship with said object. 
   
   
     4. The imaging system of  claim 3  wherein said second background color covers a major portion of said cover. 
   
   
     5. The imaging system of  claim 4  wherein said imaging system determines a plurality of boundaries of said object. 
   
   
     6. The imaging system of  claim 5  wherein said imaging system determines four boundaries of said object. 
   
   
     7. The imaging system of  claim 5  wherein said imaging device has a flat surface supporting said object. 
   
   
     8. The imaging system of  claim 7  wherein said object is paper. 
   
   
     9. The imaging system of  claim 1  wherein said imaging system converts a first color space of an image obtained from sensing said object to a second color space where the luminance of said image is enhanced over the first color space for determining said at least one boundary of said object. 
   
   
     10. The imaging system of  claim 9  wherein said first color space includes a plurality of dimensions and said second color space includes fewer dimensions than said first color space. 
   
   
     11. The imaging system of  claim 10  wherein said first color space is red, green, and blue, and said second color space is luminance. 
   
   
     12. The imaging system of  claim 1  wherein said imaging system increases the differences of values in the range of likely document edge values. 
   
   
     13. The imaging system of  claim 12  wherein said imaging system converts a first color space of an image obtained from sensing said object to a second color space where the luminance of said image is enhanced over the first color space when determining said at least one boundary of said object. 
   
   
     14. The imaging system of  claim 1  wherein an image obtained from sensing said object has a plurality of horizontal rows of pixels, said imaging system dividing said horizontal rows of pixels in a plurality of groups, each of said groups including a plurality of said horizontal rows of pixels, computing a statistical measure in a direction transverse to said horizontal row of pixels, using said statistical measure in determining said at least one boundary of said object. 
   
   
     15. The imaging system of  claim 14  wherein an image obtained from sensing said object has a plurality of vertical columns of pixels, said imaging system dividing said vertical columns of pixels in a plurality of groups, each of said groups including a plurality of said vertical columns of pixels, computing a statistical measure in a direction transverse to said vertical column of pixels, using said statistical measure in determining said at least one boundary of said object. 
   
   
     16. The imaging system of  claim 15  further comprising determining edges within the data determined as a result of computing said statistical measures. 
   
   
     17. The imaging system of  claim 14  further comprising determining edges within the data determined as a result of computing said statistical measure. 
   
   
     18. The imaging system of  claim 17  wherein a set of statistical measures in a direction transverse to said horizontal row of pixels from a plurality of said groups are statistically processed for determining said at least one boundary of said object. 
   
   
     19. The imaging system of  claim 18  wherein the result of processing said set of statistical measures are further processed to emphasize spatial regions of increased statistical measure. 
   
   
     20. The imaging system of  claim 18  wherein said determining said at least one boundary of said object is based upon a variable threshold value calculated based upon said set of statistical measures. 
   
   
     21. The imaging system of  claim 20  wherein said variable threshold value is calculated based upon a percentage of the maximum observed statistical measure. 
   
   
     22. The imaging system of  claim 1  wherein an image obtained from sensing said object has a plurality of vertical columns of pixels, said imaging system dividing said vertical columns of pixels in a plurality of groups, each of said groups including a plurality of said vertical columns of pixels, computing a statistical measure in a direction transverse to said vertical column of pixels, using said statistical measure in determining said at least one boundary of said object. 
   
   
     23. The imaging system of  claim 22  further comprising determining edges within the data determined as a result of computing said statistical measure. 
   
   
     24. The imaging system of  claim 23  wherein a set of statistical measures in a direction transverse to said vertical column of pixels from a plurality of said groups are statistically processed for determining said at least one boundary of said object. 
   
   
     25. The imaging system of  claim 24  wherein the result of processing said set of statistical measures are further processed to emphasize spatial regions of increased statistical measure. 
   
   
     26. The imaging system of  claim 24  wherein said determining said at least one boundary of said object is based upon a variable threshold value calculated based upon said set of statistical measures. 
   
   
     27. The imaging system of  claim 26  wherein said variable threshold value is calculated based upon a percentage of the maximum observed statistical measure. 
   
   
     28. An imaging system comprising:
 (a) an imaging device sensing an object; 
 (b) a backing in opposing relationship with said object; and 
 (c) wherein said imaging system determines at least one general bounding region of said object by converting a first color space of an image obtained from sensing said object to a second color space where the luminance of said image is enhanced over the first color space for determining said at least one boundary of said object. 
 
   
   
     29. The imaging system of  claim 28  wherein said first color space includes a plurality of dimensions and said second color space includes fewer dimensions than said first color space. 
   
   
     30. The imaging system of  claim 29  wherein said first color space is red, green, and blue, and said second color space is luminance. 
   
   
     31. The imaging system of  claim 28  wherein said imaging system increases the differences of values in the range of likely document edge values. 
   
   
     32. The imaging system of  claim 28  wherein an image obtained from sensing said object has a plurality of vertical columns of pixels, said imaging system dividing said vertical columns of pixels in a plurality of groups, each of said groups including a plurality of said vertical columns of pixels, computing a statistical measure in a direction transverse to said vertical column of pixels, using said statistical measure in determining said at least one boundary of said object. 
   
   
     33. The imaging system of  claim 32  further comprising determining edges within the data determined as a result of computing said statistical measure. 
   
   
     34. The imaging system of  claim 33  wherein a set of statistical measures in a direction transverse to said vertical column of pixels from a plurality of said groups are statistically processed for determining said at least one boundary of said object. 
   
   
     35. The imaging system of  claim 34  wherein the result of processing said set of statistical measures are further processed to emphasize spatial regions of increased statistical measure. 
   
   
     36. The imaging system of  claim 34  wherein said determining said at least one boundary of said object is based upon a variable threshold value calculated based upon said set of statistical measures. 
   
   
     37. The imaging system of  claim 36  wherein said variable threshold value is calculated based upon a percentage of the maximum observed statistical measure. 
   
   
     38. An imaging system comprising:
 (a) an imagine device sensing an object; 
 (b) a backing in opposing relationship with said object; 
 (c) said imaging system determining at least one general bounding region of said object; and 
 (d) wherein an image obtained from sensing said object has a plurality of horizontal rows of pixels, said imaging system dividing said horizontal rows of pixels in a plurality of groups, each of said groups including a plurality of said horizontal rows of pixels, computing a statistical measure in a direction transverse to said horizontal row of pixels, using said statistical measure in determining said at least one boundary of said object. 
 
   
   
     39. The imaging system of  claim 38  wherein an image obtained from sensing said object has a plurality of vertical columns of pixels, said imaging system dividing said vertical columns of pixels in a plurality of groups, each of said groups including a plurality of said vertical columns of pixels, computing a statistical measure in a direction transverse to said vertical column of pixels, using said statistical measure in determining said at least one boundary of said object. 
   
   
     40. The imaging system of  claim 39  further comprising determining edges within the data determined as a result of computing said statistical measures. 
   
   
     41. The imaging system of  claim 8  further comprising determining edges within the data determined as a result of computing said statistical measure. 
   
   
     42. The imaging system of  claim 41  wherein a set of statistical measures in a direction transverse to said horizontal row of pixels from a plurality of said groups are statistically processed for determining said at least one boundary of said object. 
   
   
     43. The imaging system of  claim 42  wherein the result of processing said set of statistical measures are further processed to emphasize spatial regions of increased statistical measure. 
   
   
     44. The imaging system of  claim 42  wherein said determining said at least one boundary of said object is based upon a variable threshold value calculated based upon said set of statistical measures. 
   
   
     45. The imaging system of  claim 44  wherein said variable threshold value is calculated based upon a percentage of the maximum observed statistical measure.